This invention relates in general to the construction of sensor elements and in particular to a new and useful radiation detector and to a method of making such a detector.
Radiation detectors comprising a plurality of sensor or detector elements are known. Such detectors are responsive, for example, to heat radiation or ultraviolet radiation. Detectors of this multi-sensor type are employed to produce visible images. It is known that such detectors must be operated at very low temperatures, if a high sensitivity is required. Detector elements of prior art radiation receivers of this kind may be accommodated in a vacuum space which is designed as a Dewar vessel at the same time. In the usual design, such a radiation receiver comprises a Dewar vessel formed by cup-shaped parts, with the Dewar elements being arranged on the outside of the bottom portion of the inner part. An evaporation cooler or a similar cooling element is inserted in the cavity of the inner part.
The quality of an image increases with the amount of separation spacing of the sensor elements. This, however, involves the necessity of providing an equally large number of electrical leads connecting the sensor elements to the outside of the Dewar vessel. In a prior art design, very fine metal wires are used for connecting the sensor elements, which wires are led out from the Dewar vessel in the zone where the two cup-shaped parts of the vessel are fused to each other, and serve as outer contact elements.
Since the size of such radiation receivers is necessarily limited, an increasing number of electrical leads makes it increasingly difficult to obtain a satisfactory hermetic sealing of the Dewar vessel, particularly if the radiation receiver is also exposed to high mechanical and thermal loads.